/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.volley.toolbox;

import com.android.volley.AuthFailureError;
import com.android.volley.Request;
import com.android.volley.Request.Method;

import org.apache.http.Header;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.ProtocolVersion;
import org.apache.http.StatusLine;
import org.apache.http.entity.BasicHttpEntity;
import org.apache.http.message.BasicHeader;
import org.apache.http.message.BasicHttpResponse;
import org.apache.http.message.BasicStatusLine;

import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLSocketFactory;

/**
 * An {@link HttpStack} based on {@link HttpURLConnection}.
 */
public class HurlStack implements HttpStack {

  private static final String HEADER_CONTENT_TYPE = "Content-Type";

  /**
   * An interface for transforming URLs before use.
   */
  public interface UrlRewriter {
    /**
     * Returns a URL to use instead of the provided one, or null to indicate
     * this URL should not be used at all.
     */
    public String rewriteUrl(String originalUrl);
  }

  private final UrlRewriter mUrlRewriter;
  private final SSLSocketFactory mSslSocketFactory;

  public HurlStack() {
    this(null);
  }

  /**
   * @param urlRewriter
   *          Rewriter to use for request URLs
   */
  public HurlStack(UrlRewriter urlRewriter) {
    this(urlRewriter, null);
  }

  /**
   * @param urlRewriter
   *          Rewriter to use for request URLs
   * @param sslSocketFactory
   *          SSL factory to use for HTTPS connections
   */
  public HurlStack(UrlRewriter urlRewriter, SSLSocketFactory sslSocketFactory) {
    mUrlRewriter = urlRewriter;
    mSslSocketFactory = sslSocketFactory;
  }

  @Override
  public HttpResponse performRequest(Request<?> request, Map<String, String> additionalHeaders) throws IOException,
      AuthFailureError {
    String url = request.getUrl();
    HashMap<String, String> map = new HashMap<String, String>();
    map.putAll(request.getHeaders());
    map.putAll(additionalHeaders);
    if (mUrlRewriter != null) {
      String rewritten = mUrlRewriter.rewriteUrl(url);
      if (rewritten == null) {
        throw new IOException("URL blocked by rewriter: " + url);
      }
      url = rewritten;
    }
    URL parsedUrl = new URL(url);
    HttpURLConnection connection = openConnection(parsedUrl, request);
    for (String headerName : map.keySet()) {
      connection.addRequestProperty(headerName, map.get(headerName));
    }
    setConnectionParametersForRequest(connection, request);
    // Initialize HttpResponse with data from the HttpURLConnection.
    ProtocolVersion protocolVersion = new ProtocolVersion("HTTP", 1, 1);
    int responseCode = connection.getResponseCode();
    if (responseCode == -1) {
      // -1 is returned by getResponseCode() if the response code could not be
      // retrieved.
      // Signal to the caller that something was wrong with the connection.
      throw new IOException("Could not retrieve response code from HttpUrlConnection.");
    }
    StatusLine responseStatus = new BasicStatusLine(protocolVersion, connection.getResponseCode(),
        connection.getResponseMessage());
    BasicHttpResponse response = new BasicHttpResponse(responseStatus);
    response.setEntity(entityFromConnection(connection));
    for (Entry<String, List<String>> header : connection.getHeaderFields().entrySet()) {
      if (header.getKey() != null) {
        Header h = new BasicHeader(header.getKey(), header.getValue().get(0));
        response.addHeader(h);
      }
    }
    return response;
  }

  /**
   * Initializes an {@link HttpEntity} from the given {@link HttpURLConnection}.
   * 
   * @param connection
   * @return an HttpEntity populated with data from <code>connection</code>.
   */
  private static HttpEntity entityFromConnection(HttpURLConnection connection) {
    BasicHttpEntity entity = new BasicHttpEntity();
    InputStream inputStream;
    try {
      inputStream = connection.getInputStream();
    } catch (IOException ioe) {
      inputStream = connection.getErrorStream();
    }
    entity.setContent(inputStream);
    entity.setContentLength(connection.getContentLength());
    entity.setContentEncoding(connection.getContentEncoding());
    entity.setContentType(connection.getContentType());
    return entity;
  }

  /**
   * Create an {@link HttpURLConnection} for the specified {@code url}.
   */
  protected HttpURLConnection createConnection(URL url) throws IOException {
    if (url.toString().contains("https"))
      HttpsTrustManager.allowAllSSL();
    return (HttpURLConnection) url.openConnection();
  }

  /**
   * Opens an {@link HttpURLConnection} with parameters.
   * 
   * @param url
   * @return an open connection
   * @throws IOException
   */
  private HttpURLConnection openConnection(URL url, Request<?> request) throws IOException {
    HttpURLConnection connection = createConnection(url);

    int timeoutMs = request.getTimeoutMs();
    connection.setConnectTimeout(timeoutMs);
    connection.setReadTimeout(timeoutMs);
    connection.setUseCaches(false);
    connection.setDoInput(true);

    // use caller-provided custom SslSocketFactory, if any, for HTTPS
    if ("https".equals(url.getProtocol()) && mSslSocketFactory != null) {
      ((HttpsURLConnection) connection).setSSLSocketFactory(mSslSocketFactory);
    }

    return connection;
  }

  @SuppressWarnings("deprecation")
  /* package */static void setConnectionParametersForRequest(HttpURLConnection connection, Request<?> request)
      throws IOException, AuthFailureError {
    switch (request.getMethod()) {
      case Method.DEPRECATED_GET_OR_POST:
        // This is the deprecated way that needs to be handled for backwards
        // compatibility.
        // If the request's post body is null, then the assumption is that the
        // request is
        // GET. Otherwise, it is assumed that the request is a POST.
        byte[] postBody = request.getPostBody();
        if (postBody != null) {
          // Prepare output. There is no need to set Content-Length explicitly,
          // since this is handled by HttpURLConnection using the size of the
          // prepared
          // output stream.
          connection.setDoOutput(true);
          connection.setRequestMethod("POST");
          connection.addRequestProperty(HEADER_CONTENT_TYPE, request.getPostBodyContentType());
          DataOutputStream out = new DataOutputStream(connection.getOutputStream());
          out.write(postBody);
          out.close();
        }
        break;
      case Method.GET:
        // Not necessary to set the request method because connection defaults
        // to GET but
        // being explicit here.
        connection.setRequestMethod("GET");
        break;
      case Method.DELETE:
        connection.setRequestMethod("DELETE");
        break;
      case Method.POST:
        connection.setRequestMethod("POST");
        addBodyIfExists(connection, request);
        break;
      case Method.PUT:
        connection.setRequestMethod("PUT");
        addBodyIfExists(connection, request);
        break;
      case Method.HEAD:
        connection.setRequestMethod("HEAD");
        break;
      case Method.OPTIONS:
        connection.setRequestMethod("OPTIONS");
        break;
      case Method.TRACE:
        connection.setRequestMethod("TRACE");
        break;
      case Method.PATCH:
        connection.setRequestMethod("PATCH");
        addBodyIfExists(connection, request);
        break;
      default:
        throw new IllegalStateException("Unknown method type.");
    }
  }

  private static void addBodyIfExists(HttpURLConnection connection, Request<?> request) throws IOException,
      AuthFailureError {
    byte[] body = request.getBody();
    if (body != null) {
      connection.setDoOutput(true);
      connection.addRequestProperty(HEADER_CONTENT_TYPE, request.getBodyContentType());
      DataOutputStream out = new DataOutputStream(connection.getOutputStream());
      out.write(body);
      out.close();
    }
  }
}
